Don't walk whole setting symbol table on load.

This should help avoid some deserialization work, or at least get rid
of one more thing that forces a bunch of it.

Author: jnthn

src/HLL/Actions.nqp

@@ -55,7 +55,7 @@ class HLL::Actions {
                         unless $block.symbol($key) {
                             my $lextype := nqp::lexprimspec($pad, $key);
                             if $lextype == 0 {
-                                $block.symbol($key, :scope<lexical>, :value(nqp::atkey($pad, $key)));
+                                $block.symbol($key, :scope<lexical>, :lazy_value_from($pad));
                             }
                             elsif $lextype == 1 {
                                 $block.symbol($key, :scope<lexical>, :value(nqp::atkey_i($pad, $key)), :type(int));

src/NQP/Optimizer.nqp

@@ -431,8 +431,11 @@ class NQP::Optimizer {
 
     method find_sym($name) {
         my %sym := self.find_lex($name);
-        if !(%sym =:= NQPMu) && nqp::existskey(%sym, 'value') {
-            return %sym<value>;
+        if nqp::ishash(%sym) && nqp::existskey(%sym, 'value') {
+            %sym<value>;
+        }
+        elsif nqp::ishash(%sym) && nqp::existskey(%sym, 'lazy_value_from') {
+            %sym<value> := nqp::atkey(nqp::atkey(%sym, 'lazy_value_from'), $name)
         }
         else {
             nqp::die("No compile-time value for $name");

src/NQP/World.nqp

@@ -445,8 +445,8 @@ class NQP::World is HLL::World {
             $i := $i - 1;
             my %symbols := @!BLOCKS[$i].symtable();
             for %symbols {
-                if !%seen{$_.key} && nqp::existskey($_.value, 'value') {
-                    my $value := ($_.value)<value>;
+                if !%seen{$_.key} && nqp::existskey($_.value, 'value') || nqp::existskey($_.value, 'lazy_value_from') {
+                    my $value := self.force_value($_.value, $_.key, 0);
                     unless nqp::isnull(nqp::getobjsc($value)) {
                         $wrapper[0].push(QAST::Op.new(
                             :op('bind'),
@@ -612,12 +612,7 @@ class NQP::World is HLL::World {
                 $i := $i - 1;
                 my %sym := @!BLOCKS[$i].symbol($final_name);
                 if %sym {
-                    if nqp::existskey(%sym, 'value') {
-                        return %sym<value>;
-                    }
-                    else {
-                        nqp::die("No compile-time value for $final_name");
-                    }
+                    return self.force_value(%sym, $final_name, 1);
                 }
             }
         }
@@ -633,14 +628,9 @@ class NQP::World is HLL::World {
                 $i := $i - 1;
                 my %sym := @!BLOCKS[$i].symbol($first);
                 if +%sym {
-                    if nqp::existskey(%sym, 'value') {
-                        $result := %sym<value>;
-                        @name.shift();
-                        $i := 0;
-                    }
-                    else {
-                        nqp::die("No compile-time value for $first");
-                    }                    
+                    $result := self.force_value(%sym, $first, 1);
+                    @name.shift();
+                    $i := 0;
                 }
             }
         }
@@ -658,4 +648,16 @@ class NQP::World is HLL::World {
 
         $result;
     }
+
+    method force_value(%sym, $key, int $die) {
+        if nqp::existskey(%sym, 'value') {
+            %sym<value>
+        }
+        elsif nqp::existskey(%sym, 'lazy_value_from') {
+            %sym<value> := nqp::atkey(nqp::atkey(%sym, 'lazy_value_from'), $key)
+        }
+        else {
+            $die ?? nqp::die("No compile-time value for $key") !! NQPMu
+        }
+    }
 }